hw/pci-host/q35: Initialize PCMachineState::bus in board code

The Q35 PCI host currently sets the PC machine's PCI bus attribute
through global state, thereby assuming the machine to be a PC machine.
The Q35 machine code already holds on to Q35's pci bus attribute, so can
easily set its own property while preserving encapsulation.

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230630073720.21297-4-shentey@gmail.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/i386/pc_q35.c

@@ -230,10 +230,12 @@ static void pc_q35_init(MachineState *machine)
                             x86ms->below_4g_mem_size, NULL);
     object_property_set_int(phb, PCI_HOST_ABOVE_4G_MEM_SIZE,
                             x86ms->above_4g_mem_size, NULL);
+    sysbus_realize_and_unref(SYS_BUS_DEVICE(phb), &error_fatal);
 
     /* pci */
-    sysbus_realize_and_unref(SYS_BUS_DEVICE(phb), &error_fatal);
     host_bus = PCI_BUS(qdev_get_child_bus(DEVICE(phb), "pcie.0"));
+    pcms->bus = host_bus;
+
     /* create ISA bus */
     lpc = pci_new_multifunction(PCI_DEVFN(ICH9_LPC_DEV, ICH9_LPC_FUNC), true,
                                 TYPE_ICH9_LPC_DEVICE);

hw/pci-host/q35.c

@@ -66,7 +66,6 @@ static void q35_host_realize(DeviceState *dev, Error **errp)
                                 s->mch.pci_address_space,
                                 s->mch.address_space_io,
                                 0, TYPE_PCIE_BUS);
-    PC_MACHINE(qdev_get_machine())->bus = pci->bus;
     pci->bypass_iommu =
         PC_MACHINE(qdev_get_machine())->default_bus_bypass_iommu;
     qdev_realize(DEVICE(&s->mch), BUS(pci->bus), &error_fatal);